I think i have most of the tempest symbols figured out save one. on my IPhone screen that shows the weather info by day I see the hour of the day an icon showing cloudy, rain, sunny etc. then temperature then the rain probability % followed by a number with an arrow. What is that last symbol. At first I thought it was wind or gust speed but it has no correlation to the info provided by my weaher station. Can someone help me out? Thanks
1 Like
If you are talking about the circled items,
they are showing predicted average wind speed and direction for that hour.
1 Like
Also remember that the arrows indicate winds FROM, because real meteorologistsā¦
use āFrom-iesā not āTo-iesā i.e. from the NW at 22 mph . . . or from 320Ā° at 24 kts.
Aha. Thank you all so much for the clarification. So in the example the first one (on the 10th): overcast, 39Ā°, 0% probability of rain, predicted average wind speed of 5mph from the NW. Is that correct ?
All correct. . .eXcept the wind direction. For the WeatherFlow | Tempest wind direction icon. . .it is somewhat misleading to the non-meteorological community. For their direction icon. . .although it Points to the NW. . .it actually means 180 degs opposite of that. In other words. . .the wind forecast in your first example would be FROM the SE at 5 mph. In the 3rd example the wind would be FROM the SSE at 6 mph. A quick way to remember usng the wind direction icons. . .is to use the large āopenā end of the wind icon as the āFROM-ieā. In other words . . . wind is from the SE or SSE at 5-7 mph. (to which way the wind is blowing TO (or TOwards) . .is irrellavent! Here an example winds from one of my one of Tempest devices in Bellevue, NE
Most all of the winds are FROM the NW at 13 mph. . .diminishing in speed to 2 mph from the NW. The 4th wind from the right shows wind becoming FROM the WSW at 2 mph. . .then shifting to become FROM the South at 3-4 mph by the end of the period. Just remember the wind direction is FROM (the large opening). . .not to which way is is pointing to. If you have a weather radio handy. . .you can listen to an hourly weather report.
Hereās how they term it in the hour weather observation roundup:
āAt 2pm in Omaha. . .it was mostly sunny, The temperature was 37 degrees; dewpoint was 15 degrees giving a Relative Humidity of 40%. The wind was from the N at 15 gusting to 24 mph. The pressure was 30.49 inches and Falling.ā
2 Likes
Again, thank you all. I love keeping track of the info on the weather station. I am now a little smarter.
Joe P.
1 Like
ok - so does the arrow point to where the wind is going ātoā (ala smoke would blow thattaway) or does it point to where it is coming āfromā (ala how a weathervane would appear) ?
This wind icon in this example is FROM-ie the South-Southwest (or slightly South of SW) because the ālarge openingā is From-ie the SSW. It is indeed pointing to the NNE. . .but assume for a moment that the pointer has a heavy weight attached to it. . .and the large opening at the other end is of very light weight material. The yellow arrow is being blown along the line of the windflow which is blowing FROM the SSW to the NNE.
Wind direction is a very misunderstood concept. A direction vane will always point into the wind like this. . .
. . .but itās actually pointing to the direction that wind is coming from because the tip has a weight in it and the tail-fin is extremely lighter The Tail fin (being extremely light-weight) is actually what tells the heavily-weighted pointer which way the wind is coming from. In image shown above. . the pointer is pointing into the wind. . .but it means the wind is from that direction. So for the image of the vane. . .the wind is actually blowing from Left to Right. . or blowing from the West. Quite simply. . .a wind vane always shows the direction from which the wind is blowing. In a Light and Variable wind. . .the vane will spin all over the place because the flow is so weak.
Hereās another example:
Q: Is a west wind coming from the west or blowing to the west?
A: The direction the wind is blowing is the direction the wind is coming FROM. A west wind means wind is blowing from the west to the east. Hereās the misnomer: The wind vane will point into the wind because that weighted tip is heavier than the tail fin. Even though it points to the west. . . .it is actually pointing in the direction the wind is coming From-ie the west.
Now one might say. . .ābut your two images donāt make sense. First you say the yellow arrow is pointing into the wind. . .so the wind should be From that direction (NE)ā. No. . .the yellow arrow in the red box is an icon and you use the same exact principle as the black wind vaneā¦ For the yellow arrow in the red box. . .assume the pointer has a heavily weighted tip attached to it. But for the icon. . .you have to think Two Dimensionally as opposed to a Three Dimension physical wind vane. The large opening (the āTail Finā) tells the direction the wind is from.
The Tempest engineers took care of that difficult concept for us. They created the 4 Ultrasonic Transducers underneath the top cap of the device . .so that Tempest determines the direction the wind is from . . .and its speed!
1 Like
You didnāt really answer my question or I got lost in all the wordsā¦
Does the arrow (in the WF app and/or webpage) point to where the wind is going ātoā (ala smoke would blow thattaway) or does it point to where it is coming āfromā (ala how a weathervane would appear) ?
My understanding is that the arrow in the WF is āwhere the wind is goingā However in meteorologic speak, they donāt speak that way. they say where the wind is coming from. . So if the arrow is pointing NW, they say the wind is NE at blah blah MPH. The whole weathervane thing just confused things.
You still arenāt answering the question! Is the arrow in the Tempest app a vector arrow or a weather vane arrow?
In other words, is the predicted wind direction for the 1200-1500 times in my example above generally a North wind or a South wind, meteriologically speaking.
1 Like
Or removing any possibility of jargon-related misunderstanding, is the wind āfromā the NNW ?
Generally a south wind, a vector arrow.
The smoke would blow in that direction, from the wide end of the arrow towards the pointy end.
The arrow does not behave like a weathervane would.
For my personally presented graphs to help with the confusion I include dots to indicate direction and my arrows are the same as Weatherflow displays and several other wind Apps.
cheers Ian 
1 Like